• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.519-524
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• 2006

In general, the Lohmann-type binary hologram represents its amplitude and phase by using the rectangular cell. In this paper, we adapts a circular cell to represents the amplitude and phase of holograms. In order to compare the characteristics of the circular cell with the rectangular one, we analyzed the results based on the computer simulations and various optical experiments. The results show that a clearer reconstructed image can be obtained by dividing one cell into many pixels. In the case of a uniform reconstructed image, the rectangular cell is better than the circular cell. However, as for the brightness of the reconstructed image, the circular cell is better than the rectangular one.

• Korean Journal of Human Ecology
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• v.7 no.2
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• pp.103-112
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• 1998

The purpose of this study were to compare the wearing and purchase practice of underwear items, and the attitudes toward underwear in middle school girls with those of their mothers in Chongju city. The questionnaires were to measure the demographic information, wearing and purchase practice of underwear items, and attitudes toward underwear. As statistical analysis, frequencies, $X^2-test$, and t-test were used. The results were as follows: 1. There were partially significant difference beween middle school girls and thier mothers of wearing and purchase practice of underwear. 2. The most important factor was size when they purchase their underwear. As the next important factor, middle school girls considered design, while their mother considered functional properties. 3. Middle school girls were more interested in the design aspect or brand name of underwear and less concerned about functional or practical aspects than their mothers in the attitudes toward underwear.

• Korean Journal of Human Ecology
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• v.8 no.3
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• pp.487-497
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• 1999

The purpose of this study was to investigate the relationship between the adjustment to life(school life, personal relations, home life, economic problem and time management), the clothing attitudes(status symbolism, fashionability, aesthetics, modesty, conformity, comfort aspect) and the clothing satisfaction. The questionnaires were administered to 456 university students in Chongju city to measure the demographic information, the adjustment to life and the clothing attitudes. As statistical analysis, frequencies, t-test, ANOVA, and correlation were used. The results were as follows: 1. The university students showed average state on the adjustment to their life. The adjustment to their home life and family was showed higher than other aspects, otherwise that to school life was showed lower than the others. 2. There were partially significant differences according to demographic variables of students on each aspect of the adjustment to life. 3. The university students showed moderate interest toward clothing attitudes. In the clothing attitudes, the interest toward comfort aspect was showed higher than other aspects, otherwise that toward conformity aspect was showed lower than the others. 4. There were partially significant differences according to demographic variables of students on each variable of the clothing attitudes. 5. There were partially significant correlations between each aspect of the adjustment and the clothing attitudes aspects.

• Elastomers and Composites
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• v.30 no.1
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• pp.20-31
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• 1995

The purpose of this study is to investigate the reinforcement of inorganic filler silica, treated by MDI about SBR vulcanizate. The characteristics of vulcanization, physical properties, surface properties and dynamic properties were investigated after mixing those silica with SBR and unmodified silica with SBR. In this experiment only the quantity of silica was variable. In the vulcanization characteristics tested by rheometer, S-series showed the fastest scorch $time(t_{10})$ and optimum cure $time(t_{90})$. And in test or tensile characteristics hardness, tensile strength, 100%, 300% modulus and elongation were all appeared in the order of M>S-series. The characteristic bonding of urea between unmodified silica and MDI could be confirmed in IR spectrum. The shapes of silicas treated chemically were observed by SEM. And the dispersion of the filler in the SBR composite was uniform. In the dynamic characteristics by the RDS, the order of elastic modulus G' values was as follows : M>S-series, and also the order of damping values was as follows : M>S-series.

• Applied Microscopy
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• v.28 no.2
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• pp.237-253
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• 1998

The structures of the fertilizedegg envelope in threespecies of cyprinidae, leoparddanio (Brachydanio frankei), cherry barb (Barbustitteya) and white cloudmountain fish (Tanichthys albonubes) were investigated by light and electron microscopy. The fertilized eggs of all three species have colorless, transparent, spherical and non-floted type. The egg envelopes have a single micropylewhich is thought to the pathway of sperm in the area of the animal pole. Also, an outer layersof both cherry barband white cloud mountain fish areadhesive types, but in that of leoparddanio has non-adhesivetype. In leopard danio, an outer surface ofegg envelope is covered by mushroom-likestructure, that of cherry barb is arranged by button-like structure, and that of white cloud mountain fish isarranged by rod-likestructure. Inboth leopard danioand cherrybarb, the eggenvelopes consist of three distinct layers; an outer layer, a middle layer and an inner layer, and that of white cloud mountain fish hastwo layers. An innerlayer of egg envelopein leopard danio consist of 10 layers, cherry barb has 8 layers, and white cloud mountain fish has $5\sim6$ layers.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.95-105
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• 2020

As one of the useful approaches to enhance safety managers' competencies, this study aims to suggest improvement plans in terms of education in school and on the job for safety managers. Educational needs at schools and job training institutes were surveyed with 321 safety managers in Daejon & Chongju Area. Correspondence with university professors at safety engineering departments via email was also conducted. Collected data were put into the R stochastic program in codified form and quantitatively analyzed through two-dimensional cross-tabulations and a chi-square test. With respect to school education, three academic subjects were examined. Job training was suggested to be conducted as 'training for trainers', which should be more flexible in terms of contents, method, and fees. Periodical investigation of educational needs for safety personnel who are consumers of safety education and training was also proposed.

• Elastomers and Composites
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• v.30 no.3
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• pp.218-228
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• 1995

To make filler loaded conducting rubber which has excellent electronical and physical properties, CR and NBR were mixed with barium ferrite(BaO.6Fe2O3). From the result of this study, vulcanization characteristics shows that curve is upgraded as the filler concentration increases and CR has higher torque than NBR. In physical properties, elongation being higher, modulus comes to decrease. Tear strength gradually decrease after showing the maximum point when is in the 100phr in CR. Resilience is not good to cause the increase in filler concentration. In electrical properties, conductivity becomes low when filler concentration increase. The increase of voltage makes a conductivity grown, but the rate change is weak. The influence of temperature hardly changes on increasing temperature. The morphology and the dispersion of a conductivity filler in vulcanizates through SEM were good. The more filler concentration increases, the shorter the particle interval is.

• Communications of Mathematical Education
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• v.33 no.2
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• pp.67-84
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• 2019

The purpose of this study is to investigate the effectiveness of intensive inquiry activity through intensive camp for 2 hours and 3 days in summer vacation and 100 hours of classes from March to December 2018 by selecting 2 middle school students using OKMINDMAP for creative education. It is the result. The teacher was the assistant, and the research problem was selected by two students themselves, and the variation of the fractal dimension was investigated and the Chaos game was shown to be possible in the modified Sierpinski triangle.

• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.459-465
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• 2004

The present paper is intended to investigate the influence of materials such as cement, mineral admixture and aggregate, on the estimation of compressive strength by P type schmidt hammer. According to the results, the materials of concrete, such as the types of cement, the replacing ratio of mineral admixture, the kinds and maximum size of aggregate, hardly influence on non-destructive test by P type schmidt hammer except for alumina cement, hence, P type schmidt can be applicable to most of the concrete with a wide range. Since the correlativity between the rebound value of P type schmidt hammer and compressive strength is very favorable(above coefficient of correlation 0.96) regardless of materials, it is considered that compressive strength can be estimated comparatively exactly by P type schmidt hammer. The estimating formula of compressive strength by rebound value are derived from this experiment as following. $\cdot$Horizontal strike : Fc = 0.765RH - 5.74 (R=0.965) $\cdot$ Vertical strike Fc = 0.793RV - 8.66 (R=0.959)

• Journal of architectural history
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• v.5 no.2 s.10
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• pp.25-39
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• 1996

Architectural researches on the traditional houses of Korea have been studied mainly based on the data collected in the field survey. From explosively incresed real mesurements and drawings in the field, plenty of data have been collected. Those have been the basic data for verifing and developing the theories on the traditional house. But after Korean war the researchers in South-Korea were not able to approach to the field in North Korea, so the new data of North Korea were not added any more. The poverty of real data have caused regional unbalance in the researches. This paper aims at collecting new data of traditional house in North Korea. But still being prohibited for the researchers of South Korea to approach to the field, I had to depend on the memories and experiences of the immigrants from North Korea who are now living in Kyon-Nam and Pusan Province. Through the questionnaire and drawings, they described vivid memory of their old houses. I was able to collect the data of 71 cases, which are significant and valuable as much as those of the real field are. The data include the address and site condition, family structure, economic condition, construction period of each house, The drawings by themselves show the building forms and plans, the plans of each building, and the included spaces. Although the quantity of those data is not enough for statistical analysis, it shows general tendency for analizing regional charateristics, the differnces among economical classes, and the periodical change. It opens the way for verfying the existing theory. Analizing the data, I have some conclusions as followings: a. Most of researchers have classified the dominant housing type of Hamkyong-Do as 'the double fold' type. In this study, all cases of Hamkyongbuk-do also show 'the double fold plan with Chongju-kan'. But in Hamkyongnam-do some cases show 'the double fold plan without Chongju-kan, or projecting the stable into the yard, which seem to be different type from 'the double fold plan with Chongju-kan' b. Existing theories classified the dominant housing type of Pyongahn-do as 'two buildings with pararell arrangement'. This classification is verified with the plentiful cases in this study. Futhermore, I found new tendency, that is, getting higher econnomic condition, they construct annex buildings between the main buildings. Finally their houses show 'scattered ㅁ shape'. The houses included in this two types has narrow and closed inner yard, which is different from the houses of the same shape in the south region of Korea. c. Existing theories classified the dominant housing type of Hwanghae-do as 'ㅁ sape with Daechong' type. I found many cases of 'ㅁ shape', but only two cases show 'Daechong'. 'The doble fold' type was also founded. Unfortunately very few cases were sent from Hwanghae-do, it is not enough for finding general tendency.